SONOFF DW2 WiFi/ DW2-RF Smart Door Window Sensor Door Open/Closed Detectors eWeLink App Notification Smart Home Alarm Work With Alexa Google Home Description: Keep linkage with SONOFF smart devices to create various smart scene Turn on/off your light with an action Notify you when the door/window is opened Check the opening and closing status of door/window on APP Battery-level display and low-battery reminder Allow sharing the sensor with your family to monitor and control of your home No gateway required Bluetooth low energy pairing Support to check history record on APP